GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

1

Does the engine knock when it is cold and continue for 2-3 minutes or does the knock increase with torque?

--

Go to Step 2

System OK

2

Inspect the flywheel.

Is the flywheel contacting the splash shield?

--

Go to Step 3

Go to Step 4

3

Reposition the splash shield.

Did you complete the repair?

--

Go to Step 1

--

4

Inspect the balancer and the drive pulleys.

Is either the balancer or the drive pulleys loose or broken?

--

Go to Step 5

Go to Step 6

5

Tighten or replace the balancer or the drive pulleys.

Did you complete the repair?

--

Go to Step 1

--

6

Inspect the piston-to-bore clearance.

Is the clearance greater than the specified value?

0.03 mm (0.001 in)

Go to Step 7

Go to Step 8

7

  1. Bore the cylinder and hone to size.
  2. Important: Cold engine piston knock usually disappears when the cylinder is grounded out. Cold engine piston knock, which disappears in about 1.5 minutes, is considered acceptable.

  3. Replace the piston.

Did you complete the replacement?

--

Go to Step 1

--

8

Inspect the connecting rod.

Is the connecting rod bent?

--

Go to Step 9

System OK

9

Replace the connecting rod.

Did you complete the replacement?

--

Go to Step 1

--